New PRV technology eliminates the need for a parallel or series system, so a second PRV downstream isn’t needed.
by Jim LeStage, CSI, CDT
Water control technology is integral to a plumbing system design, especially as the water pressure flowing in from a public water main to a commercial or residential system needs to be lowered to a more reasonable pounds per square inch (psi). To control high-pressure water, pressure-regulating valves (PRVs) are essential components of a building design, helping ensure safe, efficient, and reliable water delivery.
To reach the plumbing code minimum pressure of 80 psi, many plumbing systems will go through costly and time-consuming multi-valve installations; however, more efficient, state-of-the-art water control technologies are available. The following article will compare two commercial PRV installation options to help you discover how you can specify products that improve jobsite workflow and provide the water regulation each building requires.
A Look at Multi-Valve Installations
A building has high water pressure coming in from the public water main. This pressure needs to be controlled and lowered to reduce damage to the building and deliver a reliable water supply. Plumbing engineers can lower the pressure in a couple ways: specifying a PRV with a maximum inlet pressure or specifying two PRVs within one system.
For example, if the inlet water pressure to a building is 250 psi, you would need to design a system that reduces the pressure to a maximum of 80 psi to comply with plumbing codes. However, most PRVs on the market usually have a 3:1 pressure differential, meaning 83.3 psi is the lowest the water pressure could be reduced with that PRV.
Some may attempt to reduce the pressure even further to around 60 psi using a single PRV that is rated with a maximum inlet pressure of 300 psi. A downside to PRVs that can handle a higher psi is that they will usually generate unwanted noise by reverberating throughout the plumbing system, which will also create variations in water flow and pressure.
To minimize and possibly eliminate the noise and water pressure fluctuations, you may consider utilizing a second PRV immediately downstream of the first. For example, the first PRV may have an outlet pressure setting of 100 psi (well within the 3:1 differential), and the second PRV would have an outlet pressure setting of 60 psi (also well within the 3:1 ratio). However, the addition of the second PRV within the series system can add additional material costs and installation time, putting your job at risk for delays and budget constraints.
It may be time to look for a more updated, efficient solution to add to your specifications.
New PRV Technology: An Efficient Water Control Method
New water control technology on the market can alleviate both time-consuming installations and unwanted noise. New PRV technology products are designed with a differential of 10:1 to eliminate the need for a parallel or series system, so the second PRV downstream isn’t needed.
Including PRVs like this in your specs can provide the following benefits:
- Cost savings: By eliminating the need for a parallel or series system and automatic control valves, these single-cartridge PRVs reduce the cost of materials and labor.
- Efficient design: These PRVs can regulate low to maximum water flow with a single valve and have a high-pressure reduction of 10:1, which is how you can fully eliminate the need for a second valve in the plumbing series.
- Noise reduction: They are designed with micro-fingers that dissipate the water whistle associated with other PRVs. Instead, water flows across the seat, giving them a quieter operation. They also can accommodate a downstream water demand of up to 450 gallons per minute (gpm)—all with no detectable noise levels.
- Streamlined installation: When installing certain PRVs, the pressure can easily be adjusted in the field by pulling off the cap and adjusting the nut using a wrench. Also, certain PRVs can replace an automatic control valve and can be installed at any orientation—unlike regular auto control valves, which can only be installed in an upright orientation—allowing further flexibility during installation.
New and innovative products are available to provide your residential or commercial build with an up-to-date plumbing system. By looking to new PRV technology, your specifications can reflect modern solutions that provide efficient water control at the highest standards.
About the Author
Jim LeStage, CSI, CDT, is the Specification Sales Manager at RWC—a market leader and manufacturer of water control systems and plumbing solutions for residential, commercial, and industrial applications. To learn more about RWC and its family of brands, visit rwc.com.
The opinions expressed in this article are those of the author and not the American Society of Plumbing Engineers.
